D. Debehnke, RESUSCITATION TIME LIMITS IN EXPERIMENTAL PULSELESS ELECTRICAL-ACTIVITY CARDIAC-ARREST USING CARDIOPULMONARY BYPASS, Resuscitation, 27(3), 1994, pp. 221-229
Study objective: The objective of this study was to determine the time
limits of resuscitation following increasing intervals of untreated p
ulseless electrical activity using cardiopulmonary bypass as the resus
citation tool. Design: Prospective controlled laboratory investigation
using a canine model of pulseless electrical activity. Subjects: 20 m
echanically ventilated mongrel dogs of either sex under Halothane anes
thesia. Interventions: Pulseless electrical activity was produced by c
lamping the endotracheal tube. The ECG and hemodynamics were monitored
until loss of pressure fluctuations by aortic catheter. Animals were
then randomized to remain in untreated pulseless electrical activity f
or 10 min (Group I), 15 min (Group II) or 20 min (Group III). Followin
g each interval, resuscitation was begun using fixed-flow closed-chest
cardiopulmonary bypass (50 ml/kg/min) and an epinephrine infusion (4
mug/kg/min). Cardiopulmonary bypass was continued for 30 min or until
return of spontaneous circulation. Following return of spontaneous cir
culation, animals were weaned from bypass and observed for 1 h. Measur
ements and main results: Return of spontaneous circulation was achieve
d in 100% (7/7) Group I, 50% (3/6) Group II and 29% (2/7) Group III an
imals (P less-than-or-equal-to 0.02, Group I vs. Group Ill). One-hour
survival was achieved in 71% (5/7) Group I, 33% (1/3) Group II and 0%
(0/2) Group III animals (P > 0.05). Coronary perfusion pressure, bypas
s flow and arterial blood gases during reperfusion were similar betwee
n groups. Conclusion: Cardiopulmonary bypass is effective at restoring
spontaneous circulation when used early in asphyxial pulseless electr
ical activity cardiac arrest. Cardiopulmonary bypass is less effective
when used after 15 min of pulseless electrical activity with no survi
vors following 20 min of arrest.